The Dow Jones Industrial Average (DJIA), or simply the Dow (/ˈdaʊ/), is a stock market index that indicates the value of 30 large, publicly owned companies based in the United States, and how they have traded in the stock market during various periods of time.[4]
The value of the Dow is not a weighted arithmetic mean[5] and does not represent its component companies' market capitalization, but rather the sum of the price of one share of stock for each component company. The sum is corrected by a factor which changes whenever one of the component stocks has a stock split or stock dividend, so as to generate a consistent value for the index.[6]

The Industrial portion of the name is largely historical, as many of the modern 30 components have little or nothing to do with traditional heavy industry. Since the divisor is currently less than one, the value of the index is larger than the sum of the component prices. Although the Dow is compiled to gauge the performance of the industrial sector within the American economy, the index's performance continues to be influenced by not only corporate and economic reports, but also by domestic and foreign political events such as war and terrorism, as well as by natural disasters that could potentially lead to economic harm.

The components of the DJIA have changed 52 times since its beginning on May 26, 1896. General Electric had the longest continuous presence on the index, beginning in 1907 and ending in 2018. More recent changes to the index include the following:

On February 19, 2008, Chevron and Bank of America replaced Altria Group and Honeywell. Chevron was previously a Dow component from July 18, 1930, to November 1, 1999. During Chevron's absence, its split-adjusted price per share went from $44 to $85, while the price of petroleum rose from $24 to $100.

In 1884, Charles Dow composed his first stock average, which contained nine railroads and two industrial companies that appeared in the Customer's Afternoon Letter, a daily two-page financial news bulletin which was the precursor to The Wall Street Journal. On January 2, 1886, the number of stocks represented in what is now the Dow Jones Transportation Average dropped from 14 to 12, as the Central Pacific Railroad and Central Railroad of New Jersey were removed. Though comprising the same number of stocks, this index contained only one of the original twelve industrials that would eventually form Dow's most famous index.[17]

Dow calculated his first average purely of industrial stocks on May 26, 1896, creating what is now known as the Dow Jones Industrial Average. None of the original 12 industrials still remain part of the index.[18] They were:[19]

American Cotton Oil Company, a predecessor company to Bestfoods, now part of Unilever.

When it was first published in the mid-1880s, the index stood at a level of 62.76. It reached a peak of 78.38 during the summer of 1890, but ended up hitting its all-time low of 28.48 in the summer of 1896 during the Panic of 1896. Many of the biggest percentage price moves in the Dow occurred early in its history, as the nascent industrial economy matured. The 1900s would see the Dow halt its momentum as it worked its way through two financial crises; the Panic of 1901 and the Panic of 1907. The Dow would remain stuck in a range between 53 and 103 points until late 1914. The negativity surrounding the 1906 San Francisco earthquake did little to improve the economic climate.

At the start of the 1910s, the decade would begin with the Panic of 1910–1911 stifling economic growth for a lengthy period of time. History would later take its course on July 30, 1914; as the average stood at a level of 71.42 when a decision was made to close down the New York Stock Exchange, and suspend trading for a span of four and a half months. Some historians believe the exchange closed because of a concern that markets would plunge as a result of panic over the onset of World War I. An alternative explanation is that the Secretary of the Treasury, William Gibbs McAdoo, closed the exchange to conserve the U.S. gold stock in order to launch the Federal Reserve System later that year, with enough gold to keep the United States on par with the gold standard. When the markets reopened on December 12, 1914, the index closed at 74.56, a gain of 4.4 percent. This is frequently reported as a large drop, due to using a later redefinition. Reports from the time say that the day was positive.[21] Following World War I, the United States would experience another economic downturn, the post-World War I recession. The Dow's performance would remain unchanged from the closing value of the previous decade, adding only 8.26%, from 99.05 points at the beginning of 1910, to a level of 107.23 points at the end of 1919.[22]

During the 1920s, specifically In 1928, the components of the Dow were increased to 30 stocks near the economic height of that decade, which was nicknamed the Roaring Twenties. This period downplayed the influence of an early 1920s recession plus certain international conflicts such as the Polish-Soviet war, the Irish Civil War, the Turkish War of Independence and the initial phase of the Chinese Civil War. The Crash of 1929 and the ensuing Great Depression over the next several years returned the average to its starting point, almost 90% below its peak. By July 8, 1932, following its intra-day low of 40.56, the Dow would end up closing the session at 41.22. The high of 381.17 on September 3, 1929, would not be surpassed until 1954, in inflation-adjusted numbers. However, the bottom of the 1929 Crash came just 2½ months later on November 13, 1929, when intra-day it was at the 195.35 level, closing slightly higher at 198.69.[23] For the decade, the Dow would end off with a healthy 131.7% gain, from 107.23 points at the beginning of 1920, to a level of 248.48 points at the end of 1929, just before the Crash of 1929.[24]

Marked by global instability and the Great Depression, the 1930s contended with several consequential European and Asian outbreaks of war, leading up to catastrophic World War II in 1939. Other conflicts during the decade which affected the stock market included the 1936–1939 Spanish Civil War, the 1935–1936 Second Italo-Abyssinian War, the Soviet-Japanese Border War of 1939 and the Second Sino-Japanese War from 1937. On top of that, the United States dealt with a painful recession in 1937 and 1938 which temporarily brought economic recovery to a halt. The largest one-day percentage gain in the index, 15.34%, happened on March 15, 1933, in the depths of the 1930s bear market when the Dow gained 8.26 points to close at 62.10. However, as a whole throughout the Great Depression, the Dow posted some of its worst performances, for a negative return during most of the 1930s for new and old stock market investors. For the decade, the Dow Jones average was down from 248.48 points at the beginning of 1930, to a stable level of 150.24 points at the end of 1939, a loss of about 40%.[25]

During the 1950s, the Korean War, the Algerian War, the Cold War and other political tensions such as the Cuban Revolution, as well as widespread political and economic changes in Africa during the initial stages of European Decolonization, did not stop the Dow's bullish climb higher. Additionally, the U.S. would also make its way through two grinding recessions; one in 1953 and another in 1958. A 200% increase in the average from a level of 206 to 616 ensued over the course of that decade.

The Dow fell 22.61% on Black Monday (1987) from about the 2,500 level to around 1,750. Two days later, it rose 10.15% above the 2,000 level for a mild recovery attempt.

The 1970s marked a time of economic uncertainty and troubled relations between the U.S. and certain Middle-Eastern countries. To begin with, the decade started off with the ongoing Recession of 1969–70. Following that, the 1970s energy crisis ensued which included the 1973–75 recession, the 1973 oil crisis as well as the 1979 energy crisis beginning as a prelude to a disastrous economic climate injected with stagflation; the combination between high unemployment and high inflation. However, on November 14, 1972, the average closed above the 1,000 mark (1,003.16) for the first time, during a brief relief rally in the midst of a lengthy bear market. Between January 1973 and December 1974, the average lost 48% of its value in what became known as the 1973–1974 Stock Market Crash; with the situation being exacerbated by the events surrounding the Yom Kippur War. The index closed at 577.60, on December 4, 1974. During 1976, the index went above 1000 several times, and it closed the year at 1,004.75. Although the Vietnam War ended in 1975, new tensions arose towards Iran surrounding the Iranian Revolution in 1979. Other notable disturbances such as the Lebanese Civil War, the Ethiopian Civil War, the Indo-Pakistani War of 1971 and the Angolan Civil War which the U.S. and Soviet Union considered critical to the global balance of power, seemed to have had little influence towards the financial markets. Performance-wise for the decade, gains remained virtually flat, rising less than 5% from about the 800 level to 838.

The 1980s decade started with the early 1980s recession. In early 1981, it broke above 1000 several times, but then retreated. The largest one-day percentage drop occurred on Black Monday; October 19, 1987, when the average fell 22.61%. There were no clear reasons given to explain the crash, but program trading may have been a major contributing factor. On October 13, 1989, the Dow stumbled into another downfall, the 1989 Mini-Crash which initiated the collapse of the junk bond market as the Dow registered a loss of almost 7%.

On November 21, 1995, the DJIA closed above the 5,000 level (5,023.55) for the first time. Over the following two years, the Dow would rapidly tower above the 6,000 level during the month of October in 1996, and the 7,000 level in February 1997. On its march higher into record territory, the Dow easily made its way through the 8,000 level in July 1997. However, later in that year during October, the events surrounding the Asian Financial Crisis plunged the Dow into a 554-point loss to a close of 7,161.15; a retrenchment of 7.18% in what became known as the 1997 Mini-Crash. Although internationally there was negativity surrounding the 1998 Russian financial crisis along with the subsequent fallout from the 1998 collapse of the derivatives Long-Term Capital Management hedge fund involving bad bets placed on the movement of the Russian ruble, the Dow would go on to surpass the 9,000 level during the month of April in 1998, making its sentimental push towards the symbolic 10,000 level. On March 29, 1999, the average closed above the 10,000 mark (10,006.78) after flirting with it for two weeks. This prompted a celebration on the trading floor, complete with party hats. The scene at the exchange made front-page headlines on many U.S. newspapers such as The New York Times. On May 3, 1999, the Dow achieved its first close above the 11,000 mark (11,014.70). Total gains for the decade exceeded 315%; from the 2,753 level to 11,497.

Characterized by fear on the part of newer investors, the uncertainty of the 2000s (decade) brought on a significant bear market. There was indecision on whether the cyclical bull market represented a prolonged temporary bounce or a new long-term trend. Ultimately, there was widespread resignation and disappointment as the lows were revisited, and in some cases, surpassed near the end of the decade.

The Dow fell 14.3% from the mid-9,000 level to the low 8,000 level after the September 11, 2001 attacks. Exchanges were closed between September 11 and 17.

The eighth largest one-day point drop in DJIA history, and largest at the time, occurred on September 17, 2001, the first day of trading after the September 11, 2001 attacks, when the Dow fell 684.81 points, or 7.1%. However, the Dow had been in a downward trend for virtually all of 2001 prior to September 11, losing well over 1000 points between January 2 and September 10, and had lost 187.51 points on September 6, followed by losing 235.4 points on September 7.[27] By the end of that week, the Dow had fallen 1,369.70 points, or 14.3%. However, the Dow began an upward trend shortly after the attacks, and quickly regained all lost ground to close above the 10,000 level for the year.

During 2002, the average remained subdued without making substantial gains due to the stock market downturn of 2002 as well as the lingering effects of the dot-com bubble. In 2003, the Dow held steady within the 7,000 to 9,000-point level range by the early 2000s recession, the Afghan War and the Iraq War. But by December of that year, the Dow remarkably returned to the 10,000 mark. In October 2006, four years after its bear market low, the DJIA set fresh record theoretical, intra-day, daily close, weekly, and monthly highs for the first time in almost seven years, closing above the 12,000 level for the first time on the 19th anniversary of Black Monday (1987). On February 27, 2007, the Dow Jones Industrial Average fell 3.3% (415.30 points), its biggest point drop since 2001. The initial drop was caused by a global sell-off after Chinese stocks experienced a mini-crash, yet by April 25, the Dow passed the 13,000 level in trading and closed above that milestone for the first time. On July 19, 2007, the average passed the 14,000 level, completing the fastest 1,000-point advance for the index since 1999. One week later, a 450-point intra-day loss, owing to turbulence in the U.S. sub-prime mortgage market and the soaring value of the yuan,[28][29] initiated another correction falling below the 13,000 mark, about 10% from its highs.

On October 9, 2007, the Dow Jones Industrial Average closed at a record high of 14,164.53. Two days later on October 11, the Dow traded at an intra-day level high of 14,198.10,[30] a mark which would not be matched until March 2013.[31] In what would normally take many years to accomplish; numerous reasons were cited for the Dow's extremely rapid rise from the 11,000 level in early 2006, to the 14,000 level in late 2007. They included future possible takeovers and mergers, healthy earnings reports particularly in the tech sector, and moderate inflationary numbers; fueling speculation the Federal Reserve would not raise interest rates.

On September 15, 2008, a wider financial crisis became evident when Lehman Brothers filed for Chapter 11 bankruptcy along with the economic effect of record high oil prices which reached almost $150 per barrel two months earlier. When opening that morning, it immediately lost 300 points and overall the DJIA lost more than 500 points for only the sixth time in history, returning to its mid-July lows below the 11,000 level. A series of "bailout" packages, including the Emergency Economic Stabilization Act of 2008, proposed and implemented by the Federal Reserve and U.S. Treasury, as well as FDIC-sponsored bank mergers, did not prevent further losses. After nearly six months of extreme volatility during which the Dow experienced its largest one-day point loss, largest daily point gain, and largest intra-day range (more than 1,000 points), the index closed at a new twelve-year low of 6,547.05 on March 9, 2009 (after an intra-day low of 6,469.95[32] during the March 6 session), its lowest close since April 1997, and had lost 20% of its value in only six weeks.

During the early part of the 2010s, aided somewhat by the loose monetary policy practiced by the Federal Reserve, the Dow made a notable rally attempt, though with significant volatility due to growing global concerns such as the 2010 European sovereign debt crisis, the Dubai debt crisis, and the United States debt ceiling crisis. On May 6, 2010, the index lost around 400 points over the day, then just after 2:30 pm EDT, it lost about 600 points in just a few minutes, and gained the last amount back about as quickly. The intra-day change at the lowest point was 998.50 points, representing an intra-day loss of 9.2%. The event, during which the Dow bottomed out at 9,869 before recovering to end with a 3.2% daily loss at 10,520.32, became known as the 2010 Flash Crash.[33] The index closed the half-year at 9,774.02 for a loss of 7.7%.[34]

In the midst of the decade, the Dow rallied its way above the peak from October 2007. On May 3, 2013, the Dow surpassed the 15,000 mark for the first time before towering above the next few millenary milestones thanks to commendable economic reports.[35][36][37] The index closed 2014 at 17,823.07 for a gain of 71% for the five years before progress became minimal the next year.[38] However, the overwhelming economic factors exhibited in 2015 precipitated the Dow's major pullback, which questioned some as to whether this was just a correction for the first time since 2011 or a fresh, new bear market.[39][40] This led to the Dow closing at 17,425.03 for 2015, the first annual loss since 2008.[41] After nearly 14 months since the last record close, the Dow finally achieved a fresh new, central-bank debt fueled record close on July 20, 2016 at 18,595.03 along with an intraday high of 18,622.01.[42]

During the late part of the 2010s, despite anticipations of post-election selloffs, the Dow rallied significantly after Donald Trump was elected President. On January 25, 2017, the Dow hit a record high of 20,000, an increase of 1,667 points since his election in November 2016.[43] Throughout the course of the rest of 2017 and January 2018, the Dow skyrocketed past a few millenary milestones, including the symbolic 25,000 on January 4, 2018.[44] However, on February 2, 2018, the Dow suffered its biggest loss since Brexit on June 24, 2016.[45] As volatility made its return for next week, the largest intraday point drop of 1,597.08 points and largest closing point drop of 1,175.21 points were both set on February 5, 2018 although percentage changes were not as extreme as some past stock market crashes.[46] Spring and summer brought much-needed relief for the Dow as the index eventually soared to new highs. By "fall", the Dow began falling tremendously again for two major reasons: fear of sudden spikes in interest rates by the Federal Reserve[47] and woes in technology stocks.[48]

In the derivatives market, the CME Group through its subsidiaries the Chicago Mercantile Exchange (CME) and the Chicago Board of Trade (CBOT), issues Futures Contracts; the E-mini Dow ($5) Futures (YM), which track the average and trade on their exchange floors respectively. Trading is typically carried out in an Open Outcry auction, or over an electronic network such as CME's Globex platform. Dow Futures is one of the most important premarket tool and reflect the mood in which DJIA will open.

To calculate the DJIA, the sum of the prices of all 30 stocks is divided by a divisor, the Dow Divisor. The divisor is adjusted in case of stock splits, spinoffs or similar structural changes, to ensure that such events do not in themselves alter the numerical value of the DJIA. Early on, the initial divisor was composed of the original number of component companies; this initially made the DJIA a simple arithmetic average. The present divisor, after many adjustments, is less than one (meaning the index is larger than the sum of the prices of the components).
That is:

DJIA=∑pd{\displaystyle {\text{DJIA}}={\sum p \over d}}

where p are the prices of the component stocks and d is the Dow Divisor.

Events such as stock splits or changes in the list of the companies composing the index alter the sum of the component prices. In these cases, in order to avoid discontinuity in the index, the Dow Divisor is updated so that the quotations right before and after the event coincide:

With the current inclusion of only 30 stocks, critics such as Ric Edelman argue that the DJIA is not a very accurate representation of overall market performance. Still, it is the most cited and most widely recognized of the stock market indices.[52][53] Additionally, the DJIA is criticized for being a price-weighted average, which gives higher-priced stocks more influence over the average than their lower-priced counterparts, but takes no account of the relative industry size or market capitalization of the components. For example, a $1 increase in a lower-priced stock can be negated by a $1 decrease in a much higher-priced stock, even though the lower-priced stock experienced a larger percentage change. In addition, a $1 move in the smallest component of the DJIA has the same effect as a $1 move in the largest component of the average. For example, during September–October 2008, former component AIG's reverse split-adjusted stock price collapsed from $22.76 on September 8 to $1.35 on October 27; contributing to a roughly 3,000-point drop in the index.[54]

As of July 2018, Boeing and Goldman Sachs are among the highest priced stocks in the average and therefore have the greatest influence on it. Alternately, Pfizer and Cisco Systems are among the lowest priced stocks in the average and have the least amount of sway in the price movement.[55] Critics of the DJIA and most securities professionals recommend the float-adjusted market-value weightedS&P 500 or the Wilshire 5000, the latter of which includes all U.S. equity securities, as better indicators of the U.S. stock market.

A study between the correlation of components of the Dow Jones Industrial Average compared with the movement of the index finds that the correlation is higher in a time period where the average recedes and goes down. The correlation is lowest in a time when the average is flat or rises a modest amount.[56]